A method and device for driving an electromagnetic load are described, for example, in German Patent No. 44 14 609. The current flowing through the load is measured and adjusted to a setpoint value. A control means connected in series to the load is driven as a function of the current flowing through the load. Furthermore, a switching means is disposed parallel to the control means.
German Patent No. 28 40 192 describes, before the actual driving, to adjust the current flowing through a solenoid valve to a value which is not yet sufficient to actuate the solenoid valve.
Usually, power transistors are used as the switching means. If the current is adjusted by means of an analog automatic control, a very high dissipation power develops in the power transistor. The power consumption of transistors is essentially a function of the maximum permissible temperature and the degree of thermal coupling to the ambient environment.
Only two current levels with low power loss can be realized with the known device. Furthermore, a rapid circuit closing is not easily achievable.